Highly active antiretroviral therapy (HAART) has had a great impact upon reducing AIDS related morbidity and mortality. However, due to the high degree of HIV-1 variation, novel strains resistant to the present HAART cocktail of drugs have arisen. Coupled with the considerable toxicity associated with HAART, there is significant need for the discovery of new antiviral compounds. To date, retroviral vector/packaging cell systems have been used primarily in gene therapy protocols. It is hypothesized here that an HIV-1 based vector/packaging cell system can be adapted for use in high throughput screening (HTS) for drug discovery because: i)HIV-1 vector systems reproduce all aspects of virus replication in tissue culture, ii)marker genes providing simple readouts amenable to HTS can be incorporated into these systems, iii) these assays take less time than those involving replication-competent HIV-1 and are less labor intensive, and iv)a number of important safety features have been built into these systems. Preliminary studies indicate that the system provides the necessary sensitivity for drug screening. To test the hypothesis, this work will be extended to other known anti-HIV-1 drugs. Next, novel vectors, employing marker genes amenable to the HTS format, will be engineered and tested. Lastly, the system will be adapted to 96-well plates for HTS. This work should provide the foundation for a wide-ranging,safe, inexpensive, and rapid HTS that targets all aspects of HIV-1 replication reproduced in cell culture. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE